We contend that the orbitofrontal cortex, with its subcortical connections, represents a distinct subsystem whose function is to prepare the organism to respond to threatening stimuli. Variation in orbitofrontal activity yields a personality continuum. On this view the clinical syndromes obsessive-compulsive disorder (OCD) and psychopathy result from extreme deviations in circuit activity. Across the two-year project period our team will will conduct 4 experiments and construct a neural-net model. 1. In general population subjects, OCD patients and psychopathic individuals we will explore the relationship between personality measures, neurobehavioral tasks sensitive to orbitofrontal dysfunction and electrodermal response patterns. 2. Working with college students, we will test a hypothesis for performance deficits on the Object Alternation Test, one of the key measures sensitive to orbitofrontal dysfunction. 3. A pre-treatment/post-treatment assessment of OCD subjects who enter into therapy with Dr. Richard C. Raynard will determine whether symptomatic improvement corresponds to changes in orbitofrontal function and autonomic reactivity as determined by our protocol. 4. We will expand our target population to include subjects meeting DSM-4 diagnostic criteria for a broad spectrum of anxiety states and pathologies characterized by disinhibition and impulsivity, which may reflect orbitofrontal hyper- and hypometabolism, respectively. 5. We will construct a neural-net model incorporating biological variables, life-history exposure to threat and traumatic experiences, and socialization to attend to threatening stimuli. The model will illustrate how a constellation of personality characteristics results from interactions of these variables and how clinical syndromes represent extreme variations of normal behavior patterns.